Polymer reforming



Patented June 11, 1946.

Manuel H. Gorin, Everett Gorin,

Sharp, Dallas, Tex., and Irving and Lorld G. H. Welinsky,

Claymont, Del., assignors, by mesne assignments, to Socony-Vacuum Oil Company, corporated, New York,

New York N. Y., a corporation of NoDrawing. Application July 16, 1943,

, Serial No. 495,038

This invention relates to the production of liquid hydrocarbons having good antiknock characterlstics from olefins. More particularly the invention relates to a process for the production of liquid hydrocarbons of high octane number and low acid heat value suitable for use as an aviation fuel from olefins of from three to five carbon atoms or from polymers thereof.

Processes for the production of liquid hydrocarbons from the normally gaseous olefins are well known, and such prior art processes are concerned with the polymerization of the olefins'to form a polymer fraction, boiling in the gasoline range, suitable for use as a motor fuel. normal polymer product, although it has a relatively high octane rating is not suitable as an aviation fuel because of its high acid heat. The polymer may be saturated by hydrogenation to reduce its acid heat, but this increases the cost of the product and considerably reduces the octane number. Many catalysts have been proposed for use in carrying out this polymerization reaction, among which are sulphuric acid, liquid phosphoric acid, solid phosphoric acid, and alumina-silica oxide mixtures.

Processes for the production of liquid hydrocarbons suitable for use as aviation gasoline by the reaction of isoparafiinic hydrocarbons with the normally gaseous olefins to produce longer chain isoparafllns, boiling in the gasoline range and having a high octane number, are also well known. These processes are generally carried out in the liquid phase with such catalysts as sulphuric or hydrofluoric acid. There have also been proposals to carry this reaction out in the vapor phase, at moderately elevated temperatures and pressures, over such catalysts as solid phosphoric acid. Whilesuch processes are satisfactory and produce an excellent grade of aviation fuel they are limited as to the type of raw materials which they can use and yet form a product having the desired high octane rating. As a result, while such aliphatic hydrocarbons as isobutane, butylene and ethylene may be effectively utilized, they are not attractivefor the utilization of propylene, amylene, or isopentane and the other isoparafiins. Also with these socalled alkylation processes, for every mole of olefin utilized, one mole of isoparafiin is consumed.

It is a primary object of our invention to make liquid hydrocarbons suitable for use as aviation fuels from the normally gaseous or volatile liquid olefins such as propylene and amylene, with relatively small consumption of isoparaffln. Our

11 Claims. (Cl. 260683.15)

' invention is, however, equally well adapted to the The use of butylene.

Another object of our invention is to produce normally liquid isoparafflnic hydrocarbons and aromatic hydrocarbons in high yield from olefins, particularly the olefins of from three to five car bon atoms or their polymers. A still further object is to effect this production of isoparalilns and aromatics with a minimum formation of propane and butane by cracking reactions.

A further object of our invention is to produce normally liquid isoparafiinichydrocarbons and aromatic hydrocarbons from a mixture of the normally. gaseous olefins and a light isoparafiin, particularly isobutane, with a minimum consumption of the isoparaffin.

Other and further objects of our invention will be apparent from the description thereof in conjunction with the appended claims.

We have found that a liquid hydrocarbon product consisting predominantly of a mixture of saturated, branched chain aliphatic hydrocarbons and aromatic hydrocarbons may be formed by passing a mixture of an olefin and from one half to ten molar portions of a light isoparafiinic hydrocarbon at a low space velocity over a contact catalyst of the mixed oxide type. The gases may be passed over the catalyst at temperatures within the range of 275 C. to 500 C. At temperatures below 275 C. the product is largely olefinic in nature even though very long contact times are used. At temperatures above 500 (3., cracking reactions become increasingly pronounced resulting in the cracking of the products as rapidly as they are formed. The preferred temperature range is from 300 C. to 450 C. The reaction is preferably carried out at relatively high pressures within the range of from 500 to 3000 pounds per square inch. By increasing the contact time, pressures as low as pounds per square inch may be used, but the higher pressures are more desirable. The contact time varies with the activity of the particular mixed oxide catalyst used, the temperature of the gases in the reaction zone and the pressure employed. The contact time should be sufficient to allow desired reduction of the olefinic character of the product to be obtained.

The catalysts suitable for our process are com posed of a mixture of an amphoteric oxide, such as the oxides of the metals of group II and group III of the periodic table, with a hydrated oxide of a weakly acidic nature, such as silica gel, hydrated boric oxide, thoria, zirconia, stannic acid and the like. The preferred amphoteric oxides v 3 are those which are strongly amphoteric in character dissolving readily in both dilute aqueous acid and basic solutions. The oxide, inany event, must be capable of solution in both strong aqueous acid and basic solutions to be suitable for use as the amphoteric oxide constituent of our catalysts. The amphoteric oxide used should not be the amphoteric oxide of a metal easily oxidized to a non-amphoteric oxide ,of higher valence. oxide and antimony trioxide are amphoteric, but the highervalence oxides of these metals are definitely acidic and the oxides of these metals aie not suitable. The amphoteric oxide selected for use as the amphoteric oxide constituent of our catalysts should not be one which would be 7 reduced to the metallic state by the hydrocarbons at the temperature at which the alkylation process was carried out. For example, lead oxide should not be used as the amphoteric oxide constituent of a catalyst since the lead oxide would Y mixed catalysts may vary from a few tenths of one percent up to about fifteen to twenty percent. The amount of amphoteric oxide required For example, .such oxides as stannous The use of mixtures of two the acidic oxide-amphoteric oxide ratio, because of the presence of varying amounts of inert material, principally water, in the catalysts, dependto give the greatest activity varies to a certain extent depending upon the'particular oxide mixture used, and varies widely with the particular method of preparation used.

We believe that the variation in the range of preferred amphoteric oxide content in the mixed oxide catalysts of the various synthetic and natural types is the result of a variation in the concentration of amphoteric oxide present at the catalyst surface with the different methods of preparation. It is our belief, although our invention should not be limited to any particular theoretical considerations, that the amount of amphoteric oxide present in the immediate neigh-- borhood of the contact surfaces should be small relative to the amount of acidic oxide-present.

In the case of a catalyst prepared by the precipitation of aluminum oxide on neutral silica gel, the catalyst has good activity even though only a few tenths percentof the total catalyst is composed of alumina, and the amount of alumina on the catalyst 50 prepared should not be above about three or four percent. On the other hand a catme upon their origin and mode of treatment in the case of the activated natural catalysts, or their method of preparation in the case of the synthetics.v The amount of water will vary from about four or five percent to about twenty-five percent, and several percent of other materials, principally iron oxide, may be present in the natural catalytic oxide mixtures. The ratio of acidic oxide to amphotericoxide is thus a more definite value since the variation in amount of these extraneous materials is discounted in its determination. The ratio of acidic oxide to amphoteric oxide in our active catalysts will vary. from 20 to 1 to about 5Q0 to 1 in the case of the amphoteric oxidedeposited on acidic oxide type of catalyst, and from about 5 to 1 to about 50 to 1' in the case of the coprecipitated catalyst and naturally occurring catalyst.

The coprecipitated oxides and the naturally occurring mixed oxides may be activated by wash ing with a solution of a strong acid for controlled periods of time. Particularly with the coprecip itated oxides, an excessive washing even with a cold acid should be avoided, otherwise the amphoteric oxide will be removed to such an extent Q that the catalyst will be substantially inactive. The coprecipitated oxides may also be activated by treatment with a solution of a salt of a weak base with a strong acid such as an aluminum sulphate solution. One advantageous way for preparing such a coprecipitated catalyst is to pre-- cipitate a sodium silicate solution with an excess of aluminum sulphate so that the resulting supernatant solution is acid. The precipitate may then be washed with several portions of a fresh aluminum sulphate solution.

The naturally occurring oxidesshouldbe treated with rather concentrated acid solutions. Several successive treatments should be used, and

these should preferably be altered with a washing with alkaline solutions although this, is not essential. The final treatment should, of course, be an acid washing. A long digestion with hot, concentrated acid should be avoided, however, as this will substantially completely remove any amphoteric oxide from the catalyst surface and substantially inactivate the catalyst. In order that the contact surfaces of the catalyst will retain some amphoteric oxide, itwould seem that the amount of amphoteric oxide present in the catand lowers the total amphoteric oxide content to a certain extent. In the case of a naturally oc-v currin clay, or a synthetic catalyst-of the coprecipitated, mixed oxide type, the acid treatment should not be carried-out to such an extent that the acid disintegrates the structure of the catalyst, dissolving out all or nearly all of the amphoteric oxide because such treatment would mina-silica clay known as fioridin may be activated by suitable treatment. These naturally occurring mixed oxides should also contain at least several percent of the amphoteric oxide, and may contain as much as fifteen percent or even slightly higher. The amphoteric oxide content of the mixed oxide catalysts is probably. not as accurate a way of describing the composition as,

substantially completely remove all amphoteric oxide from the actual contact surfaces. Such a catalyst would be relatively inactive. In view of the great difficulty in determining the details of the actual molecular and crystalline structure of the contact surface of the catalyst, the theory advanced as to the extremely small amounts of amphoteric oxide required in the case of catalysts prepared by the precipitation of such oxide on a hydrated acidic oxide has not been proven. It does fit-in well, however,

with the requirement of considerably larger amounts of amphoteric oxide in the case of catalysts preparedby coprecipitation of the mixed oxides or by acid treatment of naturally occur ring oxide mixtures.

In the following examples and throughout the specification and the appended claims, by the use of the term "space velocity, we mean the volume of reactants as liquids entering the reaction zone per hour per unit volume of catalyst employed, unless otherwise indicated. By the term contact time we mean the actual total time of contact of the reactants in contact with the catalyst at the reaction conditions in minutes.

Our invention may be best understood by the following example illustrating a preferred mode of continuous operation thereof. The example is not to be construed, however, as limiting our invention to the mode of operation described therein.

Example Silica gel was prepared by adding water glass to sufficient excess acetic acid so that the pH of the resultant mixture was approximately 5.0. The concentration of the reactants was such that the concentration of SiOz in the total mixture was 10% by weight. A hydrogel of silica was formed which was washed free of salts, and then boiled in a solution of 0.2 N aluminum sulphate for two hours. The catalyst was then washed thoroughly and dried for two hours at 90 to 100 C.

A gas mixture containing 2,322 grams of propylene (23.6 mol percent), 122 grams of propane (1.1 mol percent), and 10,603 grams of isobutane (75.3 mol percent) was passed over the aluminasilica catalyst at 410 C. and under a pressure of 1000 pounds per square inch. The space velocity of the gas mixture over the catalyst bed was adjusted so as to give a contact'time of 2.68 minutes. The mass balance of the charge and product is given below:

' Charge Product Component Weight Grains percent Propylene Propane"- Isobutane.

n-Butane. Isopentane n-Pentane. 00+.

Olefin content per cent 1.0 Aromatic content -do 21.4 Reid vapor pressure -lbs./sq. in 9.4 A. S. T. M. octane No.:

Neat 78.9 3 cc. T. E. 92.9

The higher boiling material was practically olefin free and contained principally aromatic hydrocarbons. I

The foregoing example illustrates that a product having excellent qualities as an aviation fuel may-be made from a normal olefin-isoparamn mixture with very low consumption of isoparaflin. Without intending to limit our invention to any theoretical considerations, the following explanation of the possible reactions involved, where an olefin is reacted in admixture with an isoparafiin in the presence of a mixed oxide catalyst, is offered to illustrate the objects of our invention and to possibly account for the reaction condition requirements found necessary.

In U. S. Patent 2,068,016 to Frederick H. Gayer the use of alumina silica catalysts for the polymerization of the normally gaseous olefins, such as propylene is disclosed. While polymerization does, of course, take place in our process, its products, as such, are not the desired final reaction products. 'The olefin polymers are unsaturated and have too high an acid heat value. Generally where the polymer is later saturated, by hydrogenation, the resultin parafiin is of relatively low octane value. For example, the hydrogenated dimer of propylene consists predominantly of methyl pentanes, of low octane number.

On the other hand, while alkylation reactions can be carried out, they are subject to the disadvantages discussed' previously, and, in addition, they do not proceed very satisfactorily over the mixed oxide contact catalyst. 7

Our process seeks, therefore, to react the olefin-isoparaffin mixture with a minimum of the alkylation reaction involving the original reactants, and a minimum of the original polymer in. the final product.

The experimental facts regarding the behavior of this type of system may be correlated very well under the assumption that three types of reactions take place under the reaction conditions; namely, polymerization, hydrogen transfer, and depolymerlzation and disproportionation of polymer.

The initial reaction when an olefin is treated in the absence of an isoparaffln is the formation of polymer. Typical polymerization reactions in the case of propylene are written below:

At the same time, particularly at high temperature, a considerable amount of intermediate olefins' are formed by disproportionation of the polymer; i. e., (a) 2CsHi2" C4H8+CaHie etc.

Xylene The over-all result in the'polymerization ofolefins" under reforming conditions will be the formation of a mixture of propane, butanes andhigher parafiins boiling in the gasoline range and aromatic hydrocarbons, particularly xylene and heavier aromatics as well as smaller amounts of l toluene and benzene.

The yield of gasoline boiling hydrocarbonsis I considerably reduced in of hydrogen transfer reaction takes place;

namely, I j a ICAHIO+C3HB" C4H8+C5HB whichis followed by cr'oss polymerization and further hydrogen transfer reactions as indicated by the following equations:

C4H8+CaH5- C1H14 C1H10+iC4H10 C1H10+C4H8 A series of reactions of this type will lead to alkylation of isobutane as the predominant result to produce mainly heptanes, with smaller finic, reactant used. there will always be a mix- "ture of all the various light isoparamns once the reaction starts. The explanation oflered as to the reactions involved is given to provide a theortical basis for, the results obtained only, and our invention is not to be construed as limited to any particular theory of the process described.

amounts of other parafilns, such as propane, I

octane and the like. This result, however, is predicated on the assumption that other reactions are substantially absent, such as polymerizationof the propylene and hydrogen transfer-cyclization reactions of the polymer mentioned above. The substantial absence of, these latter reactions may be insured by maintaining a very high ratio of isoparaflln to olefin. Under these conditions it is possible to obtain alkylation as the predominant reaction.

As the ratio of olefin to isoparamn is increased the other types of reactions such as polymerization and disproportionation as well as cyclization' of the polymer will occur. A point is reached where as much isobutane is produced by hydro gen transfer between butene and polymer undergoing cyclization as is consumed by alkylation, and, as a net result, there is little or no consumption of isobutane. Under these conditions, because of the relatively smaller amount of propylene present and'its tendency to condense with the isobutane preferentially, the amount of propane formed is very much smaller than when propylene alone is treated under these conditions. In other words, at the*proper isobutane-olefinratio, a high yield of reformed saturated polymer may be obtained without consuming any substantial amount of isoparafiln.

While the foregoing explanation has been offered assuming that the reactants involved are isobutane and propylene, the considerations are perfectly general for other light isoparafiins and other olefins. Regardless of the initial isoparai'-' A specific application of our process is the p uction of aviation-base gasoline by the reaction of the volatile components of natural gasoline with olefins or oleflnic polymers. The volatile ends of natural gasoline are rich in isoparafhas such as isopentane and isohexanes. An olefin such as propylene may be reacted for example in the presence of an excess of the C5 and Co cuts of natural gasoline to produce amixture of isobutane, some n-butane and a mixture of the original natural gasoline plus a saturated gasoline containing a large amount of aromatic rich 01+ material. Sufllcient C4, C0 and C5 components are allowed to remain in the gasoline to make up an aviation-base stock of balanced volatility" system if desired.

The novel results obtained by our process are apparently due to the fact that the acid activated, mixed oxide, catalysts are not onh' good polymerization catalysts and fair alkylat ion catalysts, but will also catalyze aromatization and disproportionation-reforming reactions under the conditions used. By having 'a mixture of isoparaflln and olefin in the charge stock, the desired reactions may be efiected within the range of reaction conditions set forth.

In order to show the eifect of isobutane upon the polymerization-disproportionation reaction of propylene a series of experiments were run under the conditions, and with the results set forth in the following table. All of the examples were carried out at a pressure oi. 1000 pounds per square inch, and at the temperature indicated in the table. actants in all experiments was 2.4- cc. of liquid reactant mixture per 'cc. of catalyst per hour. The catalyst used throu hout was the same as in Example 1.' The results of Example 1 are also tabulated for convenient comparison.

Example No. a

Contact time... minutes. Mt%lt i1)ercent C1111 (basis of i-C4H10-C1H a Yield oi 01+:

Yield 05+ from i-C4H10 asis of Odi converted) Yield 00+ from CsHa is oi 0 H converts l- AHO i-clnm 11-01110 win we n-C -c 21.0 11.0 24.8 23.0 21.0 20.2 mi 21.1 10.0 18.0 21.8 20.1 18.5 10.2 20.8 r 30.0 29.8 20.4 A 03.5 05.2 114.1

54 a 0 38 2 0 0 '51 82 50 10 as 50 40 The liquid space velocity of the re- In Examples 3 and 6, there was a small in- :rease in the amount of n-butane over that :harged to the reactor. Presumably this was formed from the product polymer through disproportionation reforming reactions, and

amounted to 1.8% by weight of the butane charged.

A comparison of the results of the examples shows that the isoparaffin plays a definite part in the reaction, and very favorably influences the nature and quantity of the product obtained from the olefin. With extremely high isoparaffin-olefin molar-ratios, above ten to one, the reaction becomes predominantly oneof alkylation. This is well illustrated by a study or the results of Examples 2 and 5, wherein yields of liquid prod uct in excess of 100% on the basis of olefin charged were obtained. With the extremely high isoparafiln-olefin ratio, the amount of aromatics and unsaturates was low, also indicative of a predominantly alkylation reaction. On the other hand, in the absence of isoparaffins, the reaction is predominantly one of aromatization and polymerization. Thi is shown by the high olefin and aromatic content of the product of Examples 3, 6 and '7. A portion of the polymer is, however,

saturated by hydrogen liberated by the aromati- V zation reaction, through hydrogen exchange.

The alkylation type of reaction in Examples 2 and 5, and the polymerization type reaction in Examples 3, 6 and 7, all result in the formation of considerable amounts of normal paraflin from the olefin charge. This. is particularly true of the high temperature alkylation reaction of Example 2, where nearly half of the propylene converted'was converted to propane. In the other examples substantially one-fourth of the propylene converted was converted to propane as compared to about a one-sixth to one-seventh conversion to propane unde the condition of Examples 1 and 4. Y

By carrying out the process in the presence of a moderate excess of isoparafiin, the consumption of isoparaflin on the basis of olefin converted is low. In Examples 1 and 4 but 2% as much isobutane is converted as propylene, a compared with 36% and 64% respectively in Examples 5 and 2. An. interesting result is that, although in the alkylation type reactions of Examples 2 and 5 somewhat higher yield of liquid product is obtained, the amount of liquid product ,derived from olefin is considerably higher in Examples 1 and 4 than in any of the other examples, as is clearly hown in the last rOW of figures in the above table.

As indicated previously, we have found that the polymerization-aromatization reaction of olefins precedes to give a higher yield and a better product by admixing an isoparaflin with the olefin to effect hydrogen exchange, and disproportionation and reforming reactions. erable amounts of isoparaflins are required, about one mole of isoparaflin per two moles of an olefin such as propylene being the minimum amount required to appreciably influence the character of the product in the desired direction. On the other hand, where the amount of isoparaflin added exceeds ten mole per mole of propylene, the reaction becomes predominantly one of alkylation. l

The'preferred amount of isoparafiin to be added depends somewhat upon the particular olefin used,

the character of the product desired, and the exact temperature and pressure used. For the longer carbon chain olefins, such as amylene, an

Consid-* 2 to 6 moles of an isoparaffin per mole of increased amo'unt ofisoparaffin on a molar basis should be used over that used withthe short carbon chain olefin, propylene. Preferably our process is carried outwith theaddition of from olefin of from 3 to 5 carbon atoms. 'Where polymers of the light olefins are used in our process, the ratio of isoparafiin added should be determined on the basis of the moles of original olefin in the polymer rather than on the moles of polymer. For example with a propylene polymer, the preferred amount of isoparafiin on a molar basis would be doubled; i. e. from 4 to 10 moles of isoparafiin per mole of propylene polymer. Increasing the pressure increases the tendency towards alkylation as the principal reaction, and lowers the preferred range of isoparafiin addition. By operating with the lower isoparaffin ratio the product may be made to contain more aromatic hydrocarbons, whereas by the use of the higher isoparafiin ratios the consumption of isoparaifin will increase slightly, and the aromatic and olefinic content of the product will decrease. At a certain ratio within the preferred range, the utilization of olefin in the liquid product will be at a maximum, the exact ratio again depending upon the temperature, pressure, catalyst, and the particular olefin and isoparaflin being used in the process.

Another advantageous way of carrying out our process is to first pass the olefin alone over the catalyst at a relatively low pressure, not exceeding 100 pounds per square inch (preferably below '75 pounds per square inch) and at a relatively high gas space velocity to form the polymer therefrom. The polymer product is then mixed with isoparafiin and passed over the catalyst at the much higher pressures and much lower space velocities to get the desired reactions of this invention. By conducting thereaction with a polymer-isoparafiin mixture, the hydrogen exchange reaction in the aromatization reaction would saturate polymer rather than a mixture of polymer and propylene, particularly eliminating the formation of propane in the reaction. The polymer from the first step would be condensed out and separated from the unreacted olefin. The olefin could then be recycled for further polymerization. The isoparafiin could be mixed with the polymer and passed to another reactor containing the catalyst wherein it would be subjected to a pressure in'the range of from 500 to 3000 pounds per square inch.

An alternative procedure would be to treat the isoparaffin olefin mixture at low pressure in the presence of a mixed oxide catalyst and at a fairly high space velocity based upon cc. of olefin gas per cc. of catalyst per minute. The space velocities used should be greater than about four, measured at standard conditions, with an active polymerization catalyst to prevent the formation of much of the heavier polymer and to avoid any appreciable amount of aromatization before the unreacted propylene is removed. After removal of propylene from the isobutane-polymer mixture. the latter would be retreated at the higher pressures and low space velocities previously described. The temperature for the preliminary polymerization should preferably be within the range of from 200 to 400 C.

The unreacted isoparaffin in our process would preferablybe separated from the liquid product and admixed with fresh olefin or polymer charge for recycling through the reaction zone.

Our invention is equally applicable to the treatment 01' mixtures of olefins. For example, a

propylene-butylene mixture, or a butylenep amylene mixture. of the mixture may be mixed with normal paraffins. For example a n-butane-isobutane mixture may be used. The total isoparafiinic component of the paraflinic mixture should-be in excess of one mole per two moles of total olefinic content 01' olefin mixture. A mixture of isoparafiins, such as isobutane, isopentane, 2-methyl pentane, may also be used, alone or in mixture with normal olefins. Such gas mixtures are frequently available from topping certain natural gasolines, crude oils, and from isobutane-butylene alkylation units. I

The foregoing description of our invention is illustrative of the preferred modes of operation thereof only, and our invention should, not be limited except as indicated .'in the appended claims. v

We claim: I

1. Process for the production of liquid hydrocarbons of high octane number and low acid heat value from olefins which comprises passing the olefin in admixture with from two to six moles of a light isoparafiin of from four to six carbon atoms per mole of olefin in contact with a catalyst comprising an association of an acidic oxide and an amphoteric oxide, which has been subjected to an acid environment in the final stages of its preparation, and in which the ratio of acidic oxide to amphoteric oxide is within the range of from 500 to 1, to 5 to 1, at a temperature between 275 C. and about 500 C., at a pressure in excess of 100 pounds per square inch and for a contact time sufficient to form liquid hydrocarbons consisting predominantly of aromatic hydrocarbons and saturated paraffinic hydrocarbons from the olefin.

.2. Process for the production of liquid hydrocarbons of high octane number and low acid heat value from propylene which comprises passing the propylene in admixture with from two to six moles of a light isoparaflin'of from four to six carbon atoms per mole of olefin in contact with a catalyst comprising an association of an acidic oxide and an amphoteric oxide, which has been subjected to an acid environment in the fluid stages of its preparation, and in which the ratio carbons of high octane number and low acid heat value from propylene which comprises passing the propylene in admixture with froml2 to 6 moles of light isoparaflln of from four to six carbon atoms per mole of propylene in contact withan alumina-silica catalyst, which has been subjected to an acid environment in the final stages of its preparation, ata temperature between 300 C. and about 450 C., at apressure of from 500 to The isoparaffinic component,

( 12 hydrocarbons of high octane number and low acid' heat value from gasoline boiling olefin polymers which comprises passing the olefin polymer in admixture with from two to six moles of a light isoparaffln of fr m four to six carbon atoms per mole of the ori inal olefin monomer in contact with a catalyst comprising an association of an acidic oxide and an amphoteric oxide, which has been subjected to an acid environment in the finalstages of its preparation, and in-which the ratio of acidic oxide to amphoteric oxide is within the range of from 500 to 1 to 5 to 1,,at a tem-' perature between 275 C. to about 500 C.,-at a pressure in excess of 100 pounds per square inch and for a contact time sufilcient to form liquid hydrocarbons consisting predominantly of aromatic hydrocarbons and. saturated parafilnic hydrocarbons from the polymer.

of olefin over a catalyst comprising an association of acidic oxide and an amphoteric oxide, which 3000 pounds per square inch and for a contact time sufiicient to form liquid hydrocarbons consisting predominantly of aromatic hydrocarbons and saturated parafiinic hydrocarbons from the propylene.

4. The process of claim 3 in which the isoparaflin is isobutane.

5. The process for the production .'of liquid has been subjected to an acid environment in the final stages of its preparation, and in which the ratio of acidic oxide to amphoteric oxide is within therange of from 500 to 1 to 5 to 1 at a temperature between 200 C. and about 400 C. and at a pressure below pounds per square inch to convert a substantial portion of the olefin to gasoline boiling polymers, then raising the pressure of the mixture to within the range 01 from 500 to about 3000 pounds per square inch and passing the mixture over a catalyst comprising an association of an acidic oxide and an amphoteric oxide, which has been subjected to an acid environment in the final stages of its preparation, andin which the ratio of acidic oxide to amphoteric oxide is within the range of from 500to 1 to 5 to 1, at a temperature between 300 C. and about 450" C. to form liquid hydrocarbons consisting predominantly of aromatic hydrocarwhich has been subjected to an acid environment in the final stages of its preparation, at a temperature between 200 C. and about 400 C. and at a pressure below 100 pounds per square inch to convert a substantial portion of olefin to gasoline boiling polymers, then raising the pressure of the mixture to within the range of from about 500 to about 3000 pounds per square inch and passing the mixture over an alumina-silica catalyst which' has been subjected to an acid environment in the final stages of its preparation at a temperature between 300 C. and about 450 C. to form liquid hydrocarbons consisting predominantly 01 aromatic hydrocarbons and saturated parafiinic hydrocarbons.

8. The process for the production of liquid hydrocarbons of high octane number and low acid heat value from propylene which comprises passingthe propylene inadmixture with-from two to jected to an acid environment in the'flnal stages mers, then raising the pressure of the mixture to within the range of from 500 to about 3000 pounds per square inch and passing the mixture over an alumina-silica catalyst which has been subjected to an acid environment in the final stages of its preparation, at a temperature between 300" C and about 450 C. to form liquid hydrocarbons consisting predominantly of aromatic hydrocarbons and saturated parafilnic hydrocarbons.

9. Process for the production of liquid hydro: carbons of. high octane number and low acid heat value from the normal olefins which comprises passing the normal olefin in admixture with from two to six moles of a light isoparafiin of from four to six carbon atoms per mole of olefin in contact with an alumina-silica catalyst which has been subjected to an acid environment in the final stages of its preparation; at a temperature between 300 C. and about 450 C., at a pressure between 500 and 3000 pounds per square inch and for a contact time suficient to form liquid hydrocarbons consisting predominantly of aromatic hydrocarbons and saturated paraflinic hydrocarbons from the normal olefin.

1-0. The process of claim 9 in which the isoparaflln is isobutane.

11. The process for the production 0! hydrocarbons of high octane number and low acid heat value from the normally gaseous olefins which comprises polymerizing the olefin under conditions such that a substantial amount of gasoline boiling polymer is formed, separating the unreacted olefin from thepolymer, passing the polymer in admixture with from two to six 'moles of isobutane on the basis of the moles of original olefin monomer in the polymer in contact with a catalyst comprising an association of an acidic oxide and an amphoteric oxide, which has been subjected to an acid environment in the final stages of its preparation, and in which the ratio of acidic oxide to amphoteric oxide is within the range of from 500 to 1', to 5 to 1, at a temperature between 275 C. and about 500'C., at a pressure in excess of 100 pounds per square inch and for a contact time suflicient to form liquid hydrocarbons consisting predominantly of aromatic hydrocarbons and saturated paraffinic hydrocarbcns from the gasoline boiling polymer.

MANUEL H. GORIN. EVERETT GORIN. LORLD G. SHARP. IRVING H. WELINSKY. 

